Yep, you're right. This fits more into the army lists section but whatever, I bet a mod can relocate it no problem.
The Start Collecting formation is okay... if the 2 detachments max. limit wasnt so common in tornaments (at least in my country). A couple things you may not have noticed before you try to make a list around that concept:
1. Since the last FAQ, the archon cant choose a target if hes embarked in a vehicle. This is the biggest let down of this formation.
2. The Archon gives preferred enemy to the rest of the formation, but doesnt benefit from it himself.
3. The Raider is not specified to be a designated transport of anything else in the formation, what means kabalite warriors and the archon himself can pick up a designated transport of their own (dual splinter cannon venoms)
4. As the formation includes an archon, per the rule Retainers you can pick up a court of the archon as a part of the formation. This is important for two things:
a) you can have another dual splinter cannon venom with preferred enemy
b) If the archon joins the court unit and chooses a target, he himself benefits from the preferred enemy he transmited to the formation, as it is one of the USRs that passes on from unit to IC and viceversa. If you're going this route I reccommend Ssliz.
5. You already know this but Trueborn are an upgrade to Kabalite Warriors and thus can be taken in their place.
If you double down on this formation you have a solid core army consisting of 6 venoms, 2 units of reaver jetbikes with cluster caltrops and maybe a cuple blasters/heat lances, 2 blasterborn units and two decent close combat units in the form of Archon + Ssliz that can take the empty raider as a transport.
You can round up this composition as you like. Corpsethief claw would be a good bet, a couple grotesqueries maybe. Harlequin allies... its up to you.
It may be not the most competitive list Dark Eldar can put on the table, but it will definetly be fun. 6 venoms with preferred enemy is nothing to laugh at.